Circuit breaker



All@ 16, 1949. A. H. BAYLIS ET AL 2,479,294

CIRCUIT BREAKER Filed Oct. 18, 1945 @www ATTORN Patented ug. 16, 1949 CIRCUIT BREAKER Albert H. Baylis, Ypsilanti, Mich., and Herbert L. Rawlins, Pittsburgh, Pa., assgnors to Westinghouse Electric Corpo ration, East Pittsburgh,

Pa., a corporation of Pennsylvania Application October 18, 1945, Serial No. 623,124

14 Claims.

in one direction and is movable in both directions relative to said core structure without changing the biasing force to vary the magnetic air gap fof the trip device.

Another object of the invention is to provide `a circuit breaker with a novel electromagnetic ltrip device having a movable core structure which is movable in two different directions to trip the breaker and embodying a novel calibrating means tfor varying the tripping characteristics of the videvioe.

Another object of the invention is to provide ra circuit breaker having Va novel trip device including a core structure movable in two directions Vto trip the breaker and embodying a novel calibrating means for varying the tripping characteristics of said trip device in one direction.

Another object of the invention is to provide circuit breakers with an improved trip device including a sealed casing movable in two directions under diierent circuit conditions to trip the breaker embodying support means for supporting said casing in an initial position but permitting movement of said casing in both directions, the support means being manually adjustable to vary the tripping point in one direction While maintaining the initial position of said casing.

The novel features that are considered characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof, will best be understood from the following detailed description of one embodiment thereof, when read in connection with the accompanying drawing, in which:

Figure 1 is a side elevational view, partly in section, of a circuit breaker embodying the invention;

Fig. 2 is an enlarged fragmentary view showing the device for tripping the breaker irrespective of the direction of movement of the core structure; and

Fig. 3 is an enlarged fragmentary sectional view of the valve means for controlling the flow of fluid past the core member in the tube.

Referring to Figure 1 of the drawings, the reference numeral designates a base of strong insulating material which supports the various parts of the circuit breaker. A pair of terminals |3 and I5 are suitably secured to the base and each terminal has one or more connecting studs I9 which extend through the back of the base and serve to electrically connect the breaker to the circuit which it controls.

The upper terminal I3 has a contact block 2| of rigid conducting material secured thereto; and a rigid contact block 23 secured to the base is electrically connected to the lower terminal I5 through the energizing winding of the trip device of the breaker, which will be hereinafter described.

The contact means and mechanism of the circuit breaker illustrated are similar to the circuit breaker fully disclosed '1n Patent N0. 2,214,471 issued September 10, 1940, to Leon R. Ludwig and Merle E. Horn, and assigned to the assignee or" the present invention. Hence only a brief description of these parts will be given in this application. j

The main stationary contacts 25 and 21 are rigidly secured to the contact blocks 2| and 23, respectively; and the auxiliary stationary contacts 29 and 3| are secured to a triangularly.- shaped contact platform 33 of conducting material which is mounted on the upper portion of the block 2l for limited tilting and rocking movement by means of pins 35 projecting from the opposite sides of the platform which engage in slots 31 provided in a pair of side walls 39 secured to the block 2|. The platform 33 is biased outwardly from the base by a plurality of springs 4I and 43, and outward movement of the platform is limited by the engagement of the pins 35 with the outer ends of the slots 31 and by stop projections 45 carried by the platform adjacent its upper end. The platform 33 and, consequently, the auxiliary contacts 29 and 3| are electrically connected to the terminal I3 by means of a flexible shunt conductor 41.

The movable contact means of the circuit breaker comprises a channel-shaped contact arm 49 of conducting material which is rigidly secured to a pivoted switch member 5| by means of a plurality of screws 53. The contact arm 49 carries a main contact bridging member 55 for bridging the main contacts 25 and 21, and an auxiliary contact member 51 for engaging the stationary auxiliary contacts 29 and 3|, theauxiliary contact members 51 being secured to the upper end of the channel-shaped contact arm 49 by a plurality of screws 59.

The main lcontactbridging member 155 is formed of rigid `conducting -material, :and .is loosely mounted on the contact arm 49 for limited movement relative to the contact arm toward and away from the main contacts 25 and 21 b y means of a pair of studs 6| secured to the contact carrying arm 49, only one stud. bing shown. ,A pair of coil springs (not shown) .encircle thefstuds 6|, and are disposed between vthe contact carry, ing arm 49 and the bridging member 55-fer `biasing the bridging member tgward the stationary main contacts 25 and 21 with a predetermined force. The ends of the bridging member 55 -are beveled to lie parallel .with the beveled edges of the Contact blocks v2i and 2;3, and have .a nai-r .of contacts 61 secured thereto for `engaging the main stationarycontacts 25 and 21.

The .auxiliary :contact `member. .5:1 is formed Aof rigid conducting material, and ,has :an ,intermedi- .ate contactz69 and an arcingjcontact `1| secured .thereto Afor engaging the 'intermediate rand arcing .contacts 29 vand 3| .of :the Astationary contact means.

A viiexible shunt conductor 1.3 .electrically `connects the auxiliary contact arm L49 lto the main `stationary lcontact 'block 23. The lflexible conductor has itsupperfend-isecured to the contact arm 49 by the lower ibolts53. vThe lower end .of

the flexible shuntconductor 13 iis .secured to the Ilower Vcontact iblock .1123 .by means Aof .a-z'bolt `1 1.

The switch .member Salinas a'fyokershaped lower end -whichfisspivotalty amounted :between y.the side '.Walls of -a main-frame '1f9fgbymeans .of the :pivot -pin 8|. AThe switch member^5-| is movable about its pivot axis to open and closed circuit positions toopen andzclose thecontactmeans of'theibreaker `vby means of an operatingfmechanisrn indicated generally' `at 83.

The operating mechanism 83 -is vsupported VV"by .the mainframe S19 `andtcomprises actuating vlever 85 pivoted onapin81-carried .by the frame, and `is .connected :to the switch :member '5| `by la link 89. An operating member 9| is also .pivoted .on the pin 8:1 .forfmovementabout'the.same'axis .as the actuating levera95. The .actuating 'lever 85 -is normally andreleasablylconnected'tothe'opf verating `member. y9| vrfor' :movement :thereby by 'means `of .a pair 4of latches 293and =95, '.-which lare .pivota'll7 :mounted zon 'the .lever :185 at'ff91"and99, respectively. Thel11atch'93 .engages a roller 19| .carriedzbyitheLoperating '-mernber 19|, and :this Ylatch is, :in iturn; heldiinilatching position Eby the auxiliary Alatch :595. The operating member .19| 'is adapted -to .fibewreleasably heldffin :closed circuit pvoted rat v|i|=9, which releasably .en-gages .the roller UJI. The `auxiliary latch 95 is ..provided with a .curved :tailpiecef |2051 by means Cof which .it is released toicause-releasebfthe 1atch-931and .Springs .4| landfii.. A; er

member 9|. The'switch member 5| and the actuating lever 85 are biased to open position by means of a pair of accelerating springs |09 (only one being shown), which are connected at their upper ends to the switch member 5| and at their lower ends to the sides of the main frame 19.

To close the circuit breaker after it has been tripped open, the operating member 9| is rst moved in a counterclockwise direction about the .pivot axis 81 to the open position to eiect resetting Aof the latches and reestablishment of the releasable rigid connection between the actuating lever-8.5 and the operating member 9|. After the 1 rigid .connection -is -thus established, the operating Lmember .9| lis moved in a clockwise direction to closed positionby means of a handle i to effect `closing o f thepontaet means of the breaker. The clockwise or closing movement of the operating member V9| is limited by a portion 92 thereof striking a iixed stop 94 on the frame 19. When .the 'partsV hayebeenrnoveg ,te @losed positie@ fthe gna-in holding .late .IBS-messages the relier .4.0i to noie me oserait-ing member in closed position- Tne stop V9,4 isf-located to riem-.it .lit .overtwvel Qfthememb rsi toi .re ergs .engagement ofthe latch |93 h ber-911er 40|- .It will be notedthat the cqn M ofthe ,epslfif ing :mechanism .is .such that the mei/@H152 geniet .means is :trip-tree of the oper t'ng member smettila Gonel that is, when .the @maken tact means moveto open'msi @irrespective .of the .position oftheV .operating .memberl- The mounting of contact -ineans is sucnthatdiirineonenine of the-.breaker .the main bridging member .5 is first separated from the stationary contacts 25 Ys alnd1 2|, v.while .the auXilarr .contacts .engagement by reason of .the 19u-kwam imovmntf--. platform T33l .under the fiuenge fthe biagi-ee brldeinefmein er 2.155Y has separated aihlfdil; meds .the :main stationary contacts me miler-'mediate contacts 29 and 69 begin to separate. Thistakes place as soon .as th 3;5 llfge the-.ends

i noftheslots i311.. :Du-ring tnis'isigleftbe-arcine Goritarts 'c3-Land 7l in .engagement .due to the .reeking movement of the. contact Platform 3.3- efiter the intermediate .meterte have .Separated a predeiermineddisteeea the amine contacts ne 1| bee, o separate.V During dosing. .the contacts lengage the reverse-.erden as .Will .readily be understood. H.It be Seen .that the arc formed .during separatignfef thecontats is ,drawn only betwentheereiue .sintesis itl .and 'LL "line .circuit breaker .adapted to' .be tripped .open either manually. or .autpmaticallyf in .11esponse to predetermined oyerloadQconditions in the circuit, by .means .of atlr rnghenism'iiidcated'generally at l5. i

The trip mechanism comprises a trip 'lever 1H Which-is lnir@tally mountedntermediateits ends on' the. frame .19 byimeans Qf .apvot Spin H9. .and

electromagnetic 'trip' meal. indicated 'eenerally .at .i2 l., which lspeliable 1.1.1.1 response tothe predetermined overload .Conditions "G0-'move *the tripleverj! if! to tripping position'tocause auto- 'matieopening of the circuitbreaker.

vOne arm @|23 offthet-rip lever fl |=1 `is lonset and extends inwardly 'tof-.yard the" base VI -l of the circuit --breaker, and #hasitseinner' end disposed immechatetyabove-thetrip'meansvlsl to be enga-ged and moved by a plunger of the ele'ctrornagnetrto eiect automaticztripping .of `the breaker. vThe -ar-m :|23 of fthetrip/leverfisfprovidedwith a' pro-l l5 jection |'25Iwliic'h is adapted to engage the curved tailpiece |05 vof the auxiliary Ylatch `95 to move this latch to released position upon movement of the trip lever to tripping position. The kother arm l the `trip level H1 frfns frle 1'2"' whereby the trip lever may 4be manually moved to "tripping position to elect manuel of the `circuit breaker. A spring 12's fnnects the erm |23 or the trip .lever -|||T|71ali extensiblf tlffe'inain lheldlng laten ma se that ure spr-lng time serves te bias the main holding leftlh 'to latohii position and the trip leverto its normal inoperative position, as shown in Fig. '-1.

The electromagnet |21 *oiilpri'ses a stationary core 'lfner'nbe'r |31, a movable '-Co'r'e structure ndicated generally at |33 having "a tripmember |35 related thereto, and fan energizing windingf|`31 having one end connected '5to 'the vCim-tact block and the other end eohliec'tedto the't'erm'inal '|"5.

The stationary core member |3| is vsecured vto the base Il by means of :screws '|39 fwhic'h pass through openings in the base fand engage threaded openings in formed rover prcljectio'ns IM and |43 of the core member 113|, "Ifhe lower projection of the fixed core Ymember is again formed outwardly as at |45 to serve as a support means for the movable core structure |33.

The movable core structure |33 comprises a sealed casing |41 containing a body of oil or vother liquid vof suitable viscosity, a main core member |49 1and a sieoondary core member |5|. The main oore'member |49 is tubular and has its upper 'end closed by 'an integral part which is tapped to vreceivevthe threaded-upper end of an adjusting rod |53 which extends downwardly throughV an opening in the projection |475. A s rip |55 is disposed between a Washer |51 surl-v-mb e. rounding the rod |53 and a collar 159 lintegral with or suitably secured vtethered |53. The bottorn lei of the seale`d easin'g |41 vrests on the upper end of the rod |53. The spring y|55, therefore, by supporting the rod` 153,'res'iliently supports the entire movable core structure to permit the core structure tomove 'downwardly for a purpose to be fully described later. Y

The secondary "c'ore member |5|l is Anormally maintained in the upper end of the sealed casing means 'of a spring v`| 631 compressed between the botto-rn |6| of the sealed easing and a shoulder on the 'core member l|"5|. 'The vsecondary core melober l! is provided with an opening extending axially therethrough, through which extends a control tube |65 of non-magnetio-material. At its lower end thetube 65'rests on the bottom ,portion Il' of the sealed 'casing and'is provided with an opening |61 'for the passage of lluid. The upper end of the controltube |65 is .provided with a valve chamber |69 rigidly secured 'thereto and disposed in nested relation -n an enlargedvopening |1| in the upper end of the core member |5-|, the opening |1|' being :somewhatlarger in diameter than the valve chamber |69 to lprovide -an oil passage bypassing the valve chamber.

The upper end of the sealed casi-ng `|41 is closed by a cap |13 suitably secured as by brazing to the body of the casing so as to hermet'ically seal the casing. The cap |13 is provided with acentrally located tapped opening'and a filler-casing for the purpose of fllling the casing tothe required level with iiuid. lAfter -thecas-in-g |41 is lilled with fluid to the requiredlevel, the opening is sealed by .inserting a lscrew V| therein and brazing or soldering ltheserew'in place. The `casing |111 is not completely -lled with fluid. space beingprovided to permit expansion of the 'uid.

The upper lend of the valve'elramber :|69 is `closed by means of la disc :|11 (Fig. 533) suimbly secured thereto 'as by braizingfthe dise pro- 'against the bottom of the chamber |69 foriins fa seal. The valve 8| for-ms aFSeal forthe 'rupperend lof the tube |65 except iforth'e orice |785. `.'Avalve' dise l 31 disposed within the space belowith'e valve ll is biased .downwardly by jtl-fe force of fgfravlty and crimped at several :point's iabut lits edge fas at ISQ to permit fluid to flow thereunder fand through the orifice 185 in the 'valve '|8l. Inaddl'- non te the 'opening |61 at the lewerkencl of the tube |65, the tube is provided 'with Ia large fopening lill (Fig. 3) 'spaced 'apredetermined"distance below the chamber |69 anda small orifice '1793 located just below the bottom'of the 'valve vcham. ber for controlling the flow v4of fluid fas Willibe more fully brought out later in the description of the operation of the dev-ice.

The sealed Vcasing |41 is adaptedto bemovel upwardly under -one set `V`o'f conili'tioils `rand fdow'nwardly under another set 1of conditions to e'eo't tripping of the breaker. To'aeeompli'shthis, the trip member |35 must operate `to aotu'ate fa trip rod E upwardly to `acti-'late the "trip "lever 1'| |1 when the casing '|41 moves in either vrdirection. The trip rod |95 extends vertically 'through :an opening in a cross member 91 of 'the l"nfl'afil'l breaker frame 1e and lis provided with 'a -c'ollar 4|59 integral therewith 'for nbrrna-llyret'aining the trip rod in the position shown. The 1lower fend ofthe trip rod |595 is provided lwi'th fa head 526| which is adapted to be yengaged by 'a projection 233 on the rightha-nd end (Figs. 1 'and 2) "of the trip member |35. The -tri-p member n|35 lis supported in a bracket 2505 secured --by `rne'a'n's of screws V231 to the top ofthe @fx'ed'c'ore member GSI (see Fig. 2). The "-br'aeket is -pr'o- 'vlried with upwardly extending `Alears fille each having an inwardly extending pin ji2H fs'ecired therein. These pins extend through elongated slots 2 i3 (Fig. 2) in ea-r's2l5 formed 'downwardly from the trip vmember 1335. "The lefthandend (Figs. 1 and 2) of the trip member v'has a downward reverse bend 2 |1 which extends underneath a projection 2|9 oi the cap |13 on the upper end of the sealed 'casing |41.

The trip member |35 is providedw-ith la clearance 'opening for the screw |15 and normally rests on the flat top surface o'f rthe cap |13so that upon upward movement 'of 'the 'easing |2411 carries the trip member bodily therewith '-to actuate the trip rod |95. During lthis movement, the slots 2|3 in the ears '2|5 Lrnove freelyY over the pins 2| When the sealed casing 'TIM moves downwardly, as will be hereinafter 'desoribed-,lthe projection 2|9 on the cap |13 engages the y'bent portion 2|1 of the trip member '|35 fan-d rotates the trip member counterelockwi'se about vtll's'a pins 2|| to engage the projection 2&3 with thev trip rod |95 to effect tripping ofthe breaker.

The trip device `functions to tr-iprth'e breaker after a comparative long time .delay lnr'esponee to overload currents ir'l'tlielowe'r range Aover load current values, `witha -'shorttime delay 'in the intermediate range of overload euirrirts "up to 'a predetermined value and instantaneously in Aresponse to overload currents above said predeter- Amined value or on short circuits. These ranges of overload current values may be arbitrarily deylned as follows: The low range between 100% and 700% of normal rated current; the intermediate range from 700% tol 1000% of normal rated current and instantaneous 1000% or more -of normal rated current or short circuits.

Upon the occurrence of an overload current in the lower range of overloads, that is, up to 700% of normal current, the secondary core member starts to move downwardly forcing oil through the control tube |65 out of the orifice |93 and between the valve chamber |59 and the -Wall of the opening |1| into the upper portion vof the sealed casing above the core member. .The upward pressure of the oil in the tube |55 fraises the disc |81 against the bottom face of the valve |8| closing 4the orifice |85 but this pressure in insuiiicient to compress the spring .|83 and open the valve |8|. The downward movement of the core member |5| compresses the spring |63 and biases the entire core structure downward against the spring |55 but the force is not great enough to compress the spring |55.

As the secondary core member 55| continues its downward movement, it slowly reduces the magnetic air gap between itself and the main core member |49. After moving downwardly a vpredetermined distance the core member |5| uncovers the opening I9! in the tube |65 permitting a free iiow of oil past the core member which now increases its downward speed to rapidly close the air gap between the two core members |59 and |5| and at the same time open an air gap between the core member |5| and the upper leg of the fixed core member |3I. The entire :core structure now acts as in a solenoid and is moved upwardly to trip the breaker.

When the circuit is interrupted, by opening of the breaker contacts, the winding |31 is deenergized permitting the entire core structure to drop to its original position. The spring |83 now moves the secondary core member |5| upwardly in the sealed casing |51 forcing oil to ow downwardly through the control tube. The downward pressure of the oil through the orifices |19 and |85 (Fig. 4) causes the valve disc |81 to move downward opening the oriiice |85 and permitting free iiow of oil to thereby permit the Spring |93 to quickly restore the core member |5| to its uppermost position in the sealed casing.

An important feature of the invention is the provision of means for calibrating the time delay tripping time of the trip device. This means comprises the rod |53 which threadedly engages and adjustably supports the armature |49 and also supports the sealed casing |41 in a normal position. The rod |53 is resiliently supported by the spring |55 tb permit downward tripping movement of the sealed casing in response to overload currents above the aforesaid predetermined value. By rotating the rod |53, the armature |49 is moved upwardly or downwardly relative to the casing |1l1 and the secondary core |5| depending on the direction of rotation of the rod. It will be obvious that this movement of the armature will vary the initial air gap between the main armature |49 and the secondary core member |5| andV thereby vary the tripping point of the breaker in the low range of overload currents.

'Ihe rod |53 does not move axially'when it is rotated; consequently, the sealed casing |41 and the secondary core |5| remain in their position when the armature |49 is adjusted. The adjustment of the armature is, therefore, independent of the position of the sealed casing.

When an overload occurs inthe intermediate range of overloads between 700% and 1000% of normal rated current the force with which the secondary lcore member |5| is attracted downward is much greater due to increased energization of the winding |31. This forces the oil upwardly through the tube |65 with suicient pressure to cause opening of the valve |8| and permitsa greater iiow of oil to the upper part of the sealed casing.- The rate of movement oi the secondary core member |5| is thus increased and tripping is effected with a much shorter time delay than it would be if the valve |8| were not provided. Under this condition, the oil flows around the valve |8| and out the orices V9 in addition to the flow of oil through the orifice |93 and between the valve chamber |59 and the wall of the recess |1l. After the core member |5| uncovers the opening |9| in the control tube |65, the tripping action is the Same as that described previously in connection with low range of overload currents.

When the winding |31 is energized in response to an overload current of 1000% or over of normal rated value, or a short circuit, the secondary core member |5| is attracted downwardly with such force and speed that the oil below the core member is Iunable to flow through the control tube |65 and, therefore, moves the entire core structure including the sealed casing |41 downwardly to trip the breaker. The downward movement of the sealed casing engages the projection 2|9 of the cap |13 with the bent portion 2| 1 of the trip member |35 and rocks the trip member counterclockwise to actuate the trip rod |95 and instantaneously trip the breaker. The downward tripping movement of the core structure compresses the spring |55 which, upon deenergization of the winding |31, reacts to restore the core structure to its normal position as shown in Fig. l.

Certain features are disclosed but not claimed in the instant application which are fully disclosed and claimed in copending application Serial No. 622,469, led October 15, 1945, by H. J. Madden and assigned to the assignee of the instant invention.

From the foregoing description, it will be apparent that there is provided a novel trip device for a circuit breaker wherein a solenoid is operated in one direction to trip the breaker after a time delay and in the opposite direction to instantaneously trip the breaker. The time delay feature is hermeti'cally sealed in a casing so that its operation will remain unaffected by corrosion or foreign substances. An important feature of the invention is the provision of the Calibrating means for varying the tripping characteristics of the tripV device in the low overload range without ditsturbing the instantaneous tripping characteris ics,

The limits of the intermediate range of overloads set forth (approximately '700% to 1000% of rated current) are to be considered merely by way of example and these may be varied considerably in the manner described to suit particular requirements for instance by varying the diameter of the orices |93 and |95 and also by varying the'strength of the springs.

Having described the invention in accordance with the patent statutes, it is to be understood that various changes and modifications may be made in the structural details and combination of elements disclosed Without departing from some of the essential features of the invention. It is, therefore, desired that the language of the appended claims be given as reasonably broad interpretation as the prior art permits.

We claim as our invention:

1. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip device operable to cause automatic operation f said operating mechanism comprising an energizing winding, a magnetic circuit energized by said winding, a movable core structure disposed in said magnetic circuit comprising a sealed casing movable to trip said operating mechanism, an armature for moving said casing, a core member within said casing for delaying tripping movement of said casing, said core member cooperating with said armature to provide a magnetic air gap in said magnetic circuit, and manually operable adjustable means for adjustably varying the air gap without disturbing the position of said casing.

2. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the comb-ination of an electromagnetic trip device operable to cause automatic operation of said operating mechanism, a movable core structure operable in either of two directions to trip said operating mechanism comprising a sealed casing, an armature operable to move said casing, a core member within said casing cooperating with said armature to provide a inagnetic air gap, means resiliently supporting said movable core structure, and manual means for varying the air gap independently of said resilient means and without changing the stress of said resilient means.

3. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of an electromagnetic trip device operable to cause automatic operation of said operating mechanism comprising an energizing winding, a magnetic circuit energized by said winding, a movable structure movable in two directions to trip said operating mechanism, an armature for moving said movable structure, said armature providing an air gap in said magnetic circuit, spring means supporting said armature and said movable structure, said spring permitting movement of said movable structure in one direction, and adjusting means for manually moving said armature relative to said movable structure and said spring without changing the stress of said spring or the position of said movable structure to vary the magnetic air gap.

4. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of an electromagnetic trip device operable to cause automatic operation of said operating mechanism, said trip device comprising an energizing winding, a magnetic circuit energized by said winding, a movable core structure movable in two directions to trip said operating mechanism, an armature for operating said movable core structure, said armature disposed to provide an air gap in said magnetic circuit, a spring biasing said armature and said core structure against movement in one direction, and adjustable means between said spring and said armature and said movable core structure supporting said armature and said movable core structure, said adjustable means being manually operable to move said armature relative to said movable core structure to vary the magnetic air gap without varying the tension of said spring and without changing the position oi said movable core structure.

5. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip device for causing automatic operation of said operating mechanism comprising an energizing winding, a sealed casing movable to trip said operating mechanism, an armature for moving said casing in one direction to trip said operating mechanism, a core member in said casing operable to delay movement of said casing by said armature, said core member being at times operable to move said casing in another direction to trip said operating mechanism, spring means supporting said sealed casing and biasing said casing against movement in said other direction, and adjustable means supported by said spring and supporting said armature and said casing, said means being manually adjustable to vary the position of said armature relative to said casing.

6. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip device operable to cause automatic operation of said operating mechanism comprising a fixed core member, a sealed casing movable in two directions, an armature operable to move said casing in one direction, a movable core member in said casing operable in response to overload currents below a predetermined value to delay movement of said casing in said one direction, said movable core member being operable in response to overload currents above said predetermined value to operate said casing in another direction to instantaneously trip said operating mecha-nismeans biasing said casing against movement in said other direction, and manual means for adjusting said armature relative to said casing to vary the time delay tripping characteristic.

7. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of an electromagnetic trip device operable to cause automatic operation of said operating mechanism comprising an energizing winding, a. sealed casing movable in one direction to trip said operating mechanism after a time delay and in another direction to instantaneously trip operating mechanism, an armature operable under certain circuit conditions to move said casing in said one direction, a core member disposed in said casing and operable to delay movement of said casing in said one direction, said core member being operable under certain other circuit conditions to move said casing in said other direction, means biasing said armature and said casing against movement in said other direction, and manual means sup- -ported by said biasing means and operable to move said armature relative to said casing and said core member.

8. In a circuit breaker comprising relatively movable contacts and operating means therefor, the combination of a trip device operable to cause automatic operation of said operating means comprising a magnetic circuit, an energizing winding, a movable core member, a sealed casing movable by said movable core member to trip said operating means, a, secondary core member disposed in said casing to delay tripping movement of said movable core member, and

means for manually adjusting said movable core member relative to said casing to vary the tripping characteristic of said trip device.

9. In a circuit breaker comprising relatively movable contacts and operating means therefor, the combination oan electromagnetic trip device operable to cause automatic operation of said operating means, said trip device comprising a fixed magnetizable member, an energizing Windingfa movable core member operable upon energization of said Winding, a sealed casing movable by said movable core member to effect tripping of said operating means, time delay means disposedin said casing operableupon energization of said Winding to delay movement of said casing, and meansv for manually adjusting said movable core relative to said casing to vary the tripping characteristic of said trip device.

10. In a circuit breaker comprising relatively movable contacts and operating means therefor, the combination of an electromagnetic trip device comprising a iixed magnetizable member, an energizing Winding, a, sealed casing movable to trip said operating means, a movable core member operable upon energization of said winding to move said casing, time delay means disposed within said casing and operable upon energization of said Winding to delay tripping movement of saidcasing, means supporting said movable core member and said casing, said supporting means being manually adjustable to move said movable core member relative to said easing to vary the tripping characteristic of said trip device.

11. In a circuit breaker comprising relatively movable contacts and operating means therefor, the combination of an electromagnetic trip device comprising a xed magnetizable member, an energizing Winding, a sealed casing movable to trip said operating means, a movable core Ymember operable upon energization of said winding to move said casing, time delay means disposed Within said casing and operable upon energization of said winding to delay tripping movement of said casing, means'supporting said movable core member and said casing, said supporting means being manually adjustable to move said movable core member relative to said casing while maintaining said casing in fixed position to vary the tripping characteristic of said trip device.

Y 12. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of an electromagnetic trip device comprising a xed magnetizable member, an energizing Winding, a sealed casing movable to trip said operating mechanism, a movable core member operable upon energization of said winding to move said casing, a member Supporting said casing inY xed initial position relatively Vto said winding and adiustably supporting said movable core member relative to said Winding, means disposed in said casing operable upon energization of said Winding to delay movement of said casing, and said support means being manually adjustable to'vary the position of said movable core member relative to said Winding While maintaining said casing in its fixed initial position relative to said winding.

13. In a circuit breaker comprising relatively movable contacts and operating means therefor, the combination of a trip device operable to cause automatic operation of said breaker comprising an energizing winding, a movable core structure movable in tvvo directions to trip said operating means, said movable core structure comprising a sealed casing, an armature operable to move said casing in one direction to trip said operating means after a time delay, time delay means comprising a core member disposed within said casing and operable in response to overload currents below a predetermined value to delay operation of said movable core structure in said one direction, said core member being operable in response to overload current above said predetermined value to move said movable core structure in the other direction to instantaneouslyrtrip said operating means, means supporting said movable core structure in an initial position relative to said winding, and said supporting means being manually operable to adjust said armature relative to said movable core structure and said winding without disturbing the initial position of said core structure to thereby vary the minimum overload required to move said core structure in said one direction.

1li. In a circuit breaker comprising relatively movable contact meansthe combination of a trip device operable to eiiect automatic opening of said contact means, said trip device comprising a magnetic circuit, an energizing Winding, a movable core member, a sealed casing containing a body of uid movable in one direction by said movable core member to effect automatic opening of said contact means, a secondary core member disposed in said casing, means restricting displacement of fluid to retard tripping movement of said movable core member with a relatively long time delay, valve means operable to increase displacement of fluid 'to thereby retard tripping movement of said movable core member With a relatively short time delay, said secondary core member being at times operable to move said casing in another direction to eiect instantaneous opening of said contact means, and manual adjustableV means for adjusting said movable core member relative to said casing to vary the time delay and instantaneous tripping characteristics.

ALBERT H. BAYLIS. HERBERT L. RAWLINS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,072,932 Wilokens Mar. 9, 1937 2,357,959 Kouyoumjian Sept. 12, 1944 2,373,998 Burgwin Apr. 17, 1945 2,451,962 Lindstrom Oct. 12, 1948 

